Evaluating Semantic Knowledge Through a Semantic Association Task in Individuals With Dementia.

Conceptual knowledge is supported by multiple semantic systems that are specialized for the analysis of different properties associated with object concepts. Various types of semantic association between concrete concepts-categorical (CA), encyclopedic (EA), functional (FA), and visual-encyclopedic (VEA) associations-were tested through a new picture-to-picture matching task (semantic association task, SAT). Forty individuals with Alzheimer's disease (AD), 13 with behavioral variant of frontotemporal dementia (bv-FTD), 6 with primary progressive aphasia (PPA), and 37 healthy participants were tested with the SAT. Within-group comparisons highlighted a global impairment of all types of semantic association in bv-FTD individuals but a disproportionate impairment of EA and FA, with relative sparing of CA and VEA, in AD individuals. Single-case analyses detected dissociations in all dementia groups. Conceptual knowledge can be selectively impaired in various types of neurodegenerative disease on the basis of the specific cognitive process that is disrupted.

Anatomical integrity within the inferior fronto-occipital fasciculus and semantic processing deficits in schizophrenia spectrum disorders.

The core symptoms of schizophrenia spectrum disorders (SSD) include abnormal semantic processing which may rely on the ventral language stream of the human brain. Thus, structural disruption of the ventral language stream may play an important role in semantic deficits observed in SSD patients. Therefore, we compared white matter tract integrity in SSD patients and healthy controls using diffusion tensor imaging combined with probabilistic fiber tractography. For the ventral language stream, we assessed the inferior fronto-occipital fasciculus [IFOF], inferior longitudinal fasciculus, and uncinate fasciculus. The arcuate fasciculus and corticospinal tract were used as control tracts. In SSD patients, the relationship between semantic processing impairments and tract integrity was analyzed separately. Three-dimensional tract reconstructions were performed in 45/44 SSD patients/controls ("Bern sample") and replicated in an independent sample of 24/24 SSD patients/controls ("Basel sample"). Multivariate analyses of fractional anisotropy, mean, axial, and radial diffusivity of the left IFOF showed significant differences between SSD patients and controls (p(FDR-corr) < 0.001, ηp2 = 0.23) in the Bern sample. Axial diffusivity (AD) of the left UF was inversely correlated with semantic impairments (r = -0.454, p(FDR-corr) = 0.035). In the Basel sample, significant group differences for the left IFOF were replicated (p < .01, ηp2 = 0.29), while the correlation between AD of the left IFOF and semantic processing decline (r = -0.376, p = .09) showed a statistical trend. No significant effects were found for the dorsal language stream. This is direct evidence for the importance of the integrity of the ventral language stream, in particular the left IFOF, in semantic processing deficits in SSD.

Grammatical Ability Predicts Relative Action Naming Impairment in Primary Progressive Aphasia.

BACKGROUND: Findings from several studies have indicated that participants with nfvPPA and participants with svPPA exhibit different patterns on action and object naming tasks, while other recent studies have found that neither participants with nfvPPA nor participants with svPPA show a significant difference in accuracy between object naming and action naming. AIMS: The goal of this study was to test the hypothesis that relative action naming impairment is associated with grammatical ability in PPA, rather than a specific subtype of PPA. METHODS & PROCEDURES: Thirty-four participants with PPA completed the Boston Naming Test, the Action Naming subtest of the Boston Diagnostic Aphasia Examination, and the Northwestern Anagram Test, which was used to measure grammatical ability. Z-scores for the two naming tasks were calculated based on normative data from unimpaired controls. For each participant with PPA, the relative action naming impairment was calculated by subtracting the object naming z-score from the action naming z-score. Linear regression analysis was then used to evaluate the role of grammatical ability as a predictor of relative action naming impairment, while controlling for age, education, cognitive ability (as measured by the Montreal Cognitive Assessment), and semantic ability (as measured by the Pyramids and Palm Trees test). The interaction between grammatical ability and each control variable was also examined. OUTCOMES & RESULTS: The main effect of grammatical ability was a significant predictor of relative action naming impairment, while none of the control variables was a significant predictor. However, the interaction between grammatical ability and semantic ability was also significant. CONCLUSIONS: Individuals who have both grammatical impairment and semantic impairment have the largest relative action naming impairment. These individuals may benefit from a treatment that focuses on the retrieval of verbs and their arguments.

Using a Discourse Task to Explore Semantic Ability in Persons With Cognitive Impairment.

This paper uses a discourse task to explore aspects of semantic production in persons with various degree of cognitive impairment and healthy controls. The purpose of the study was to test if an in-depth semantic analysis of a cognitive-linguistic challenging discourse task could differentiate persons with a cognitive decline from those with a stable cognitive impairment. Both quantitative measures of semantic ability, using tests of oral lexical retrieval, and qualitative analysis of a narrative were used to detect semantic difficulties. Besides group comparisons a classification experiment was performed to investigate if the discourse features could be used to improve classification of the participants who had a stable cognitive impairment from those who had cognitively declined. In sum, both types of assessment methods captured difficulties between the groups, but tests of oral lexical retrieval most successfully differentiated between the cognitively stable and the cognitively declined group. Discourse features improved classification accuracy and the best combination of features discriminated between participants with a stable cognitive impairment and those who had cognitively declined with an area under the curve (AUC) of 0.93.

Behavioural and neuroimaging changes after naming therapy for semantic variant primary progressive aphasia.

The objectives of this study were to examine the effects of a successful naming intervention on naming performance and brain activity in individuals with the semantic variant of primary progressive aphasia (svPPA). Four participants with svPPA were scanned while performing phonologically- and semantically-based tasks before and after an intense, 20-h naming therapy that followed the principles of errorless learning whereby errors were eliminated from the learning process. Five healthy control participants were scanned at the outset of the study and did not receive treatment. The results showed that in svPPA participants, successful re-learning of forgotten vocabulary was accompanied by activation of a larger network in bilateral brain regions and that the level of activation in the left anterior lobe may be inversely correlated with severity of semantic impairment. Our findings have implications for treatment in svPPA patients and suggest that semantic cues can improve naming, in spite of significant semantic impairment. The results indicate that intensive language therapy can lead to behavioural gains and neuroplastic changes even in individuals with more advanced anterior temporal lobe atrophy.

Semantic and syntactic processing of mass and count nouns: data from dementia.

In the present research, we investigated the processing of Italian mass and count nouns and of their semantic and morphosyntactic attributes in people with neurodegenerative disease. The performance of a group of 26 Italian participants with Alzheimer's disease was studied in a semantic judgment task and a syntactic judgment task. Results were analyzed by means of mixed-effect models, revealing an interaction between task and stimulus category: The probability for correct responses to mass stimuli was significantly lower than that for count stimuli, but only in the semantic task. These findings confirm the major semantic impairment in dementia and suggest that mass nouns have particular features that make them more prone to impairment than count nouns for a progressively degenerating brain.

Perfil de errores en la prosucción de palabras en etapas iniciales de la enfermedad alzheimer / Words production profile errors in early stages of Alzheimer's disease

Las tareas de Denominación por confrontación visual (DCV) y fluidez verbal (FV) son amplia-mente utilizadas para evaluar el funcionamiento cognitivo de personas con diagnóstico de enfer-medad de Alzheimer (EA), un desempeño más bajo con respecto a controles, ha sido asociado a un deterioro la memoria semántica. El objetivo de este estudio fue comparar el desempeño de pacientes con EA leve con un grupo control en tareas de fluidez verbal y denominación por confrontación visual; analizando los errores cometidos por los participantes a fin de comprobar si las fallas en estas tareas tienen origen en el déficit de la memoria semántica. Los resultados muestran una gran heterogeneidad en los procesos cognitivos vinculados a la producción oral de palabras en personas con EA. Estos resultados sugieren la necesidad de evaluar a cada paciente de forma individual por medio del análisis cuantitativo y sobre todo cualitativo e interpretar los signos y síntomas independientemente de la patología

The tasks of visual confrontation naming (DCV) and verbal fluency (VF) are widely used to assess cognitive functioning in persons diagnosed with Alzheimer's disease (AD), lower perfor-mance relative to controls, has been associated with a semantic memory impairment. The goal of this study was to compare the performance of patients with mild AD with a control group on tasks of verbal fluency and visual confrontation naming; analyzing the errors made by the par-ticipants in order to ascertain whether the failure in these tasks are rooted in semantic memory deficits. The results show a great heterogeneity in production-related words in persons with AD cognitive processes. These results suggest the need to evaluate each patient individually and es-pecially by means of qualitative and quantitative analysis to interpret the signs and symptoms regardless of pathology